Several kinds of bis-dioxopiperazine derivatives have been already reported. Among them, especially known as compounds having antitumor activity are 1,2-bis(4-morpholinomethyl-3,5-dioxopiperazin-1-yl)ethane (see Abstract, 8th International Congress of Pharmacology p 441, 1981), dl-1,2-bis(4-morpholinomethyl-3,5-dioxopiperazin-1-yl)propane (see (European Patent Publication No. 0125475A1) and 1,2-bis(4-isobutoxycarbonyloxymethyl-3,5-dioxopiperazin-1-yl)ethane (see Abstract, 14th International Congress of Chemotherapy p 324, 1985 and European Patent Publication No. 0140327A2).
Still, there has been a demand for a bis-dioxopiperazine derivative having more excellent antitumor activity than those known compounds.